Changes in all-cause and cause-specific excess mortality before and after the Omicron outbreak of COVID-19 in Hong Kong

Background

While coronavirus 2019 (COVID-19) deaths were generally underestimated in many countries, Hong Kong may show a different trend of excess mortality due to stringent measures, especially for deaths related to respiratory diseases. Nevertheless, the Omicron outbreak in Hong Kong evolved into a territory-wide transmission, similar to other settings such as Singapore, South Korea, and recently, mainland China. We hypothesized that the excess mortality would differ substantially before and after the Omicron outbreak.

Methods

We conducted a time-series analysis of daily deaths stratified by age, reported causes, and epidemic wave. We determined the excess mortality from the difference between observed and expected mortality from 23 January 2020 to 1 June 2022 by fitting mortality data from 2013 to 2019.

Results

During the early phase of the pandemic, the estimated excess mortality was -19.92 (95% confidence interval (CI) = -29.09, -10.75) and -115.57 (95% CI = -161.34, -69.79) per 100 000 population overall and for the elderly, respectively. However, the overall excess mortality rate was 234.08 (95% CI = 224.66, 243.50) per 100 000 population overall and as high as 928.09 (95% CI = 885.14, 971.04) per 100 000 population for the elderly during the Omicron epidemic. We generally observed negative excess mortality rates of non-COVID-19 respiratory diseases before and after the Omicron outbreak. In contrast, increases in excess mortality were generally reported in non-respiratory diseases after the Omicron outbreak.

Conclusions

Our results highlighted the averted mortality before 2022 among the elderly and patients with non-COVID-19 respiratory diseases, due to indirect benefits from stringent non-pharmaceutical interventions. The high excess mortality during the Omicron epidemic demonstrated a significant impact from the surge of COVID-19 infections in a SARS-CoV-2 infection-naive population, particularly evident in the elderly group.

Effect of surgical intervention for childhood OSA on blood pressure: A randomized controlled study

OBJECTIVE

To investigate the effect of surgical intervention on 24-h ABP in children with OSA. It was hypothesized that blood pressure would improve following adenotonsillectomy.

METHODS

This was a two-centered investigator-blinded randomized controlled trial. Non-obese pre-pubertal children aged 6-11 years with OSA (obstructive apnea-hypopnea index, OAHI >3/h) underwent 24-h ABP monitoring at baseline and 9 months after the randomly assigned intervention, i.e. Early Surgery (ES) or Watchful Waiting (WW). Intention-to-treat analysis was performed.

RESULTS

137 subjects were randomized. Sixty-two (Age: 7.9y ± 1.3, 71% boys) and 47 (Age: 8.5y ± 1.6, 77% boys) participants from the ES and WW groups, respectively completed the study. Changes in ABP parameters were similar in the ES and WW groups (nighttime systolic BP z-scores: +0.03 ± 0.93 vs. -0.06 ± 1.04, p = 0.65; nighttime diastolic BP z-scores: -0.20 ± 0.95 vs. -0.02 ± 1.00, p = 0.35) despite a greater improvement in OSA in the ES group. However, a reduction in nighttime diastolic BP z-score correlated with improvements in OSA severity indexes (r = 0.21-0.22, p < 0.05), and a significant improvement in nighttime diastolic BP z-score [-0.43 ± 1.01, p = 0.027] following surgery was observed in participants with severe preoperative OSA (OAHI ≥10/h). The ES group had a significant increase in body mass index z-score after surgery [+0.27 ± 0.57, p < 0.001], which correlated with the increase in daytime systolic BP z-score (r = 0.2, p < 0.05).

CONCLUSION

Surgical treatment did not lead to significant improvements in ABP in OSA children except in those with more severe disease. The improvement in BP was partially masked by the weight gain following surgery.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn.

REGISTRATION NUMBER

ChiCTR-TRC-14004131).

Determining meteorologically-favorable zones for seasonal influenza activity in Hong Kong

Investigations of simple and accurate meteorology classification systems for influenza epidemics, particularly in subtropical regions, are limited. To assist in preparing for potential upsurges in the demand on healthcare facilities during influenza seasons, our study aims to develop a set of meteorologically-favorable zones for epidemics of influenza A and B, defined as the intervals of meteorological variables with prediction performance optimized. We collected weekly detection rates of laboratory-confirmed influenza cases from four local major hospitals in Hong Kong between 2004 and 2019. Meteorological and air quality records for hospitals were collected from their closest monitoring stations. We employed classification and regression trees to identify zones that optimize the prediction performance of meteorological data in influenza epidemics, defined as a weekly rate > 50^th percentile over a year. According to the results, a combination of temperature > 25.1℃ and relative humidity > 79% was favorable to epidemics in hot seasons, whereas either temperature < 16.4℃ or a combination of < 20.4℃ and relative humidity > 76% was favorable to epidemics in cold seasons. The area under the receiver operating characteristic curve (AUC) in model training achieved 0.80 (95% confidence interval [CI], 0.76-0.83) and was kept at 0.71 (95%CI, 0.65-0.77) in validation. The meteorologically-favorable zones for predicting influenza A or A and B epidemics together were similar, but the AUC for predicting influenza B epidemics was comparatively lower. In conclusion, we established meteorologically-favorable zones for influenza A and B epidemics with a satisfactory prediction performance, even though the influenza seasonality in this subtropical setting was weak and type-specific.

91Is rainfall associated with paediatric acute gastroenteritis in an affluent setting? A 21-Year Retrospective Investigation

Background

Although many literatures demonstrated heavy rainfall was associated with an increased risk of acute gastroenteritis via contaminated food and water, we hypothesized there is no association between rainfall and paediatric acute gastroenteritis in a setting with high-standard food and water hygiene.

Methods

Intestinal infection-related hospital admissions data during 1998-2018 for children under 5 years of age in Hong Kong were collected. Meteorological data were collected from the Hong Kong Observatory. A distributed lag nonlinear model was employed to examine the associations between meteorological factors and the risk of hospital admissions due to acute gastroenteritis.

Results

Rainfall did not exhibit a statistically significant association with the risk of paediatric admission due to acute gastroenteritis but low temperature, low and high relative humidity did. The risk was 6.3% higher (95% confidence interval: 0.3% to 12.6%) when temperature was at 15.1oC (i.e. the 5th percentile). The adjusted relative risk was statistically significantly higher when relative humidity was ≤73.0% or ≥ 84.0%.

Conclusions

Text: We suggest rainfall playing a minor role in disease transmission via contaminated food and water in affluent societies like Hong Kong. Instead, we speculate low temperature and humidity extremes have greater impact on transmission through increased stability and infectivity of enteric viruses.

Key messages

Weather plays a minor role in food and water contamination in affluent societies.

Low temperature and humidity extremes might improve survival of enteric viruses.

A 21-year retrospective analysis of environmental impacts on paediatric acute gastroenteritis in an affluent setting

BACKGROUND

Extreme weather events happen more frequently along with global warming and they constitute a challenge for public health preparedness. For example, many investigations showed heavy rainfall was associated with an increased risk of acute gastroenteritis. In this study, we examined the associations between different meteorological factors and paediatric acute gastroenteritis in an affluent setting in China controlling for pollutant effects.

METHODS

Aggregated total weekly number of intestinal infection-related hospital admissions, and meteorological and air pollution data during 1998-2018 in Hong Kong were collected and analysed by a combination of quasi-Poisson generalized additive model and distributed lag nonlinear model. Study population was restricted to children under 5 years of age at the time of admission.

RESULTS

While heavy rainfall did not exhibit a statistically significant association with the risk of paediatric admission due to intestinal infections, low temperature and humidity extremes (both relative humidity and vapour pressure) did. Compared with the temperature at which the lowest risk was detected (i.e. 22.5 °C), the risk was 6.4% higher (95% confidence interval: 0.0% to 13.0% at 15.1 °C (i.e. the 5th percentile)). We also found the risk of paediatric admission was statistically significantly associated with an increase in the number of extreme cold days in a week over the study period.

CONCLUSION

Cold condition may have greater impact on disease transmission through increased stability and infectivity of enteric viruses in affluent settings like Hong Kong and thus resulted in an increased risk for paediatric acute gastroenteritis. On the contrary, an insignificant impact from heavy rainfall and high temperature may indicate a minor effect on disease transmission through bacterial growth in contaminated food and water. With the identified impacts of weather factors, extreme weather events are likely to distort the prevalence and seasonal pattern of diarrhoeal diseases in the future.

Short-term association among meteorological variation, outdoor air pollution and acute bronchiolitis in children in a subtropical setting

OBJECTIVES

To examine the association among acute bronchiolitis-related hospitalisation in children, meteorological variation and outdoor air pollution.

METHODS

We obtained the daily counts of acute bronchiolitis-related admission of children≤2 years old from all public hospitals, meteorological data and outdoor air pollutants' concentrations between 1 January 2008 and 31 December 2017 in Hong Kong. We used quasi-Poisson generalised additive models together with distributed lag non-linear models to estimate the associations of interest adjusted for confounders.

RESULTS

A total of 29 688 admissions were included in the analysis. Increased adjusted relative risk (ARR) of acute bronchiolitis-related hospitalisation was associated with high temperature (ambient temperature and apparent temperature) and was marginally associated with high vapour pressure, a proxy for absolute humidity. High concentration of NO₂ was associated with elevated risk of acute bronchiolitis admission; the risk of bronchiolitis hospitalisation increased statistically significantly with cumulative NO₂ exposure over the range 66.2-119.6 µg/m³. For PM₁₀, the significant effect observed at high concentrations appears to be immediate but not long lasting. For SO₂, ARR increased as the concentration approached the 75th percentile and then decreased though the association was insignificant.

CONCLUSIONS

Acute bronchiolitis-related hospitalisation among children was associated with temperature and exposure to NO₂ and PM₁₀ at different lag times, suggesting a need to adopt sustainable clean air policies, especially to target pollutants produced by motor vehicles, to protect young children's health.

False-positive SARS-CoV-2 serology in 3 children with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute febrile and eruptive disease with systemic vasculitis predominantly affecting young East Asian children. Recent reports showed that children with KD-like disease from KD low prevalence regions had positive SARS-CoV-2 serology despite a negative SARS-CoV-2 polymerase chain reaction (PCR) in respiratory samples.

OBJECTIVES

To describe 3 pediatric Kawasaki Disease patients with false positive SARS-CoV-2 serology.

STUDY DESIGN

We retrospectively recruited children with KD diagnosed during the COVID-19 outbreak in Hong Kong. Clinical characteristics and laboratory test results including SARS-CoV-2 PCR results were retrieved. We performed a microparticle-based immunoassay for the detection of IgG against nucleoprotein (NP) and spike protein receptor binding domain (RBD), and a microneutralization assay for the detection of neutralizing antibodies.

RESULTS

Three Chinese children with typical KD were identified. They had no epidemiological links with COVID-19 patients and tested negative for SARS-CoV-2 NPA PCR. They were treated with IVIG and aspirin, and were discharged without complications. Subsequently 2 of them were tested positive against anti-RBD and anti-NP antibodies and 1 was tested positive against anti- RBD antibodies. However, microneutralization assay showed that neutralizing antibodies were absent, suggesting a false-positive IgG result.

CONCLUSION

Detection of neutralizing antibodies is recommended to confirm previous SARS-CoV-2 infection in IgG-positive but PCR-negative patients.

Palivizumab for Infants < 29 Weeks in Hong Kong without a Clear-Cut Season for Respiratory Syncytial Virus Infection-A Cost-Effectiveness Analysis

AIM

To evaluate the cost-effectiveness of palivizumab prophylaxis for premature infants born <29 weeks in Hong Kong.

METHOD

We evaluated the hospitalization rate for respiratory syncytial virus (RSV) infection within the first 12 months of discharge of a cohort of preterm infants born between 2010 and 2014 at two local hospitals.

RESULTS

In total, 40 of 135 infants were given palivizumab. The hospitalization rate for premature infants <29 weeks was reduced from 15.8 to 5% (p = 0.096) and that for infants <27 weeks was reduced from 33.3 to 8.7% (p = 0.046). In the former group, the incremental cost-effectiveness ratio per hospital admission prevented (ICER/HAP) was US dollar (USD) 24 365. In the latter subgroup, the ICER/HAP was USD 3108.

CONCLUSION

The cost-effectiveness as measured for infants <27 weeks is more favorable than that for infants <29 weeks.

Efficacy of commercial household insecticide aerosol sprays against Aedes aegypti (Linn.) under simulated field conditions

A simulated field study on the efficacy of commercial household aerosol insecticides was conducted. The bioefficacy of three pyrethroid aerosols, designated as PA1, PA2 and PA3, was tested in cabins furnished to simulate bedroom conditions. Each aerosol product was tested against lab-bred Aedes aegypti mosquitoes based on the insecticide manufacturers' recommended dosages. Ten cages with mosquitoes were placed in the following locations: one cage in the middle of the room; two each on and underneath the bed; three each placed inside, behind and on top of the wardrobe; and four placed on and in the desk. With the desk, each cage was placed inside each of three drawers (totally closed, partially closed and opened). Prior to the experiments, the discharge rate of each aerosol can was determined. Ten to 20 lab-bred 2-5 day-old sugar-fed Ae. aegypti adult mosquitoes were placed inside the test cages. The aerosol was then discharged into the cabin at the recommended dosage. After 30 minutes, the mosquitoes were transferred into clean paper cups and their mortality recorded after 24 hours. All the aerosols induced complete or very high mortality in the caged Ae. aegypti females, except in the cages hidden completely inside the drawers and wardrobes. Insecticide droplet analysis indicated variable uniformity of the droplets was produced. The aerosol insecticides were effective against mosquitoes provided they were used in accordance with the manufacturers' recommendations.

Pharyngomalacia as a cause of severe neonatal stridor

A male neonate presented at 24 hours with stridor and respiratory distress. Flexible bronchoscopy showed pharyngomalacia, i.e. complete pharyngeal wall collapse during inspiration. Assessment of upper airway dynamics is emphasised. Pharyngomalacia seems to be a self-limiting condition in our case.

Application of artificial neural networks to establish a predictive mortality risk model in children admitted to a paediatric intensive care unit

INTRODUCTION

Paediatric risk of mortality and paediatric index of mortality (PIM) are the commonly-used mortality prediction models (MPM) in children admitted to paediatric intensive care unit (PICU). The current study was undertaken to develop a better MPM using artificial neural network, a domain of artificial intelligence.

METHODS

The purpose of this retrospective case series was to compare an artificial neural network (ANN) model and PIM with the observed mortality in a cohort of patients admitted to a five-bed PICU in a Hong Kong non-teaching general hospital. The patients were under the age of 17 years and admitted to our PICU from April 2001 to December 2004. Data were collected from each patient admitted to our PICU. All data were randomly allocated to either the training or validation set. The data from the training set were used to construct a series of ANN models. The data from the validation set were used to validate the ANN and PIM models. The accuracy of ANN models and PIM was assessed by area under the receiver operator characteristics (ROC) curve and calibration.

RESULTS

All data were randomly allocated to either the training (n=274) or validation set (n=273). Three ANN models were developed using the data from the training set, namely ANN8 (trained with variables required for PIM), ANN9 (trained with variables required for PIM and pre-ICU intubation) and ANN23 (trained with variables required for ANN9 and 14 principal ICU diagnoses). Three ANN models and PIM were used to predict mortality in the validation set. We found that PIM and ANN9 had a high ROC curve (PIM: 0.808, 95 percent confidence interval 0.552 to 1.000, ANN9: 0.957, 95 percent confidence interval 0.915 to 1.000), whereas ANN8 and ANN23 gave a suboptimal area under the ROC curve. ANN8 required only five variables for the calculation of risk, compared with eight for PIM.

CONCLUSION

The current study demonstrated the process of predictive mortality risk model development using ANN. Further multicentre studies are required to produce a representative ANN-based mortality prediction model for use in different PICUs.

Obstructive sleep apnoea in children with Down syndrome

INTRODUCTION

Children with Down syndrome (DS) are prone to develop obstructive sleep apnoea (OSA) for a combination of reasons, including small upper airway, midfacial hypoplasia, micrognathia and muscular hypotonia. The objective of this study was to compare the prevalence of OSA in DS children, with or without snoring, with snoring children matched for gender, age and weight for height.

METHODS

DS children were prospectively recruited from the Hong Kong Down Syndrome Association. All recruited DS children underwent a sleep polysomnography (PSG) in our sleep laboratory. The same number of patients without DS who underwent sleep PSG in the same period were enrolled as controls after they were matched for gender, age and weight for height. OSA was defined as apnoea-hypopnoea index (AHI) greater than 1.5.

RESULTS

22 DS patients and 22 snoring controls completed the overnight PSG. The mean age of DS children and snoring controls was 10.82 +/- 5.93 and 10.27 +/- 5.68 years, respectively. The prevalence of OSA was 59 percent in DS children and 32 percent in snoring controls. Median and interquartile range (IQR) of AHI of DS children (median 1.80, IQR is 0.40 to 7.10) were significantly higher than those of controls (median 0.50, IQR is 0.00 to 2.03, p-value equals 0.041). Out of 13 DS children with OSA, eight of them (61.5 percent) had no habitual snoring.

CONCLUSION

59 percent of DS children in the current series were found to have OSA and they were more likely to develop OSA than controls. Nearly 40 percent of DS children with OSA did not have habitual snoring.

Kawasaki disease in Hong Kong, 1994 to 2000

OBJECTIVE

To describe the epidemiology, clinical characteristics, and management of Kawasaki disease in children in Hong Kong.

DESIGN

Retrospective survey of medical records from July 1994 to June 1997, and prospective data collection from July 1997 to June 2000.

SETTING

Hospitals with a paediatric unit in Hong Kong.

PATIENTS

Patients diagnosed with Kawasaki disease between July 1994 and June 2000 in public hospitals in Hong Kong.

MAIN OUTCOME MEASURES

Incidence of Kawasaki disease and coronary artery aneurysm rates.

RESULTS

A total of 696 cases of Kawasaki disease were reported. There were 435 (62.5%) boys and 261 (37.5%) girls giving a male to female ratio of 1.7:1. The age ranged from 1 month to 15 years 5 months with a median of 1.7 years. Infants (<1 year) constituted the largest group of patients (223, 32.0%) and overall, 638 (91.7%) were younger than 5 years. Skin rash, conjunctivitis, and oral signs were among the principal clinical features present in over 80% of cases. Prominent cervical lymph nodes larger than 1.5 cm were less commonly found (24%). Coronary artery aneurysms or ectasia were present in 15.7% (109/696), 8.5% (59/696), and 5.0% (35/696) of patients at 2, 4, and 8 weeks, respectively. The incidence of Kawasaki disease per 100,000 children under 5 years was significantly higher in the prospective study period than in the retrospective period (39 vs 26, P<0.001).

CONCLUSION

The incidence of Kawasaki disease is high in Hong Kong and is 39 per 100,000 children below 5 years of age. The coronary artery aneurysm prevalence is 5%. Intravenous gamma-globulin and high-dose aspirin is the mainstay of treatment.

Assessment of the Pediatric Index of Mortality (PIM) and the Pediatric Risk of Mortality (PRISM) III score for prediction of mortality in a paediatric intensive care unit in Hong Kong

OBJECTIVE

To compare two models (The Pediatric Risk of Mortality III score and Pediatric Index of Mortality) for prediction of mortality in a paediatric intensive care unit in Hong Kong.

DESIGN

Prospective case series.

SETTING

A five-bed paediatric intensive care unit in a general hospital in Hong Kong.

PATIENTS

All patients consecutively admitted to the unit between April 2001 and March 2003.

MAIN OUTCOME MEASURES

Scores for both models compared with observed mortality.

RESULTS

A total of 303 patients were admitted to the paediatric intensive care unit during the study period. The median age was 2 years, with an interquartile range of 7 months to 7 years. The male to female ratio was 169:134 (55.8%:44.2%). The median length of hospital stay was 3 days. The overall predicted number of deaths using The Pediatric Risk of Mortality III score was 10.2 patients whereas that by Pediatric Index of Mortality was 13.2 patients. The observed mortality was eight patients. The area under the receiver operating characteristics curve for the two models was 0.910 and 0.912, respectively.

CONCLUSION

The predicted mortality using both prediction models correlated well with the observed mortality.

Embryotrophic factor-3 from human oviductal cells enhances proliferation, suppresses apoptosis and stimulates the expression of the β1 subunit of sodium–potassium ATPase in mouse embryos

BACKGROUND

Embrytrophic factor-3 (ETF-3) from human oviductal cells enhanced the development of mouse preimplantation embryos. This report studied the embryotrophic mechanisms of the molecule.

METHODS AND RESULTS

Mouse embryos were incubated with ETF-3 for 24 h at different stages of development. ETF-3 treatment between 96 and 120 h post-HCG increased the cell count of blastocysts, whilst treatment between 72 and 96 h post-HCG enhanced the expansion and hatching of the blastocysts. ETF-3 increased the cell number of the embryos by suppressing apoptosis and increasing proliferation as determined by TUNEL and bromodeoxyuridine uptake assays, respectively. Real-time quantitative PCR showed that the in vivo developed and ETF-3-treated blastocysts had a significantly higher mRNA copy number of Na/K-ATPase-beta1, but not of hepsin, than that of blastocysts cultured in medium alone. The former gene was associated with cavitation of blastocysts while the latter was related to hatching of blastocyst. The beneficial effect of ETF-3 on blastocyst hatching was also seen when ETF-3-supplemented commercially available sequential culture medium for human embryo culture was used to culture mouse embryos.

CONCLUSIONS

ETF-3 improves embryo development by enhancing proliferation, suppressing apoptosis and stimulating expression of genes related to blastocyst cavitation. Supplementating human embryo culture medium with ETF-3 may improve the success rate in clinical assisted reproduction.

Obstructive sleep apnoea syndrome and obesity in children

OBJECTIVE

To review data on children who have both obesity and obstructive sleep apnoea syndrome.

DATA SOURCE

Pubmed and MEDLINE (Ovid) literature search using the following key words: obstructive sleep apnea syndrome, obesity, and children.

STUDY SELECTION

Literature and data on obesity-associated obstructive sleep apnoea syndrome in children.

DATA EXTRACTION

Review of relevant information and data.

DATA SYNTHESIS

Different definitions of obesity and obstructive sleep apnoea syndrome in children were used in different studies, which made it difficult to compare results from different studies conducted in different countries. Nonetheless, obstructive sleep apnoea syndrome was found to be moderately prevalent among obese children-namely, 13% to 36%. The severity of obstructive sleep apnoea syndrome was positively related to the degree of obesity. Blood pressure was found to be elevated in obese children with obstructive sleep apnoea syndrome. Weight reduction is an effective treatment.

CONCLUSION

Children with obesity and obstructive sleep apnoea syndrome face a double challenge. A holistic approach to management requires a clear understanding of how both problems interact.

Hepatotoxicity and persistent renal insufficiency after repeated supratherapeutic paracetamol ingestion in a Chinese boy

Paracetamol has always been regarded as a useful and safe drug. The risk of toxicity with repeated supratherapeutic paracetamol is an underrecognised condition. We report on a 12-month-old boy who presented with hepatotoxicity, disseminated intravascular coagulation and persistent renal insufficiency 4 days after repeated ingestion of a supratherapeutic dosage of paracetamol. To the best of our knowledge, this is the first reported case of paediatric chronic paracetamol poisoning among the Chinese population. In addition, persistent renal insufficiency has not been a previously reported feature of chronic paracetamol poisoning. We propose that renal damage is the result of the synergistic effect of hypoperfusion and paracetamol overdose.

BP and arterial distensibility in children with primary snoring

STUDY OBJECTIVE

While previous studies have suggested an association between obstructive sleep apnea and cardiovascular complications, the effects of primary snoring in children on daytime systemic BP and arterial distensibility remain unknown.

DESIGN AND PATIENTS

To determine the effects of primary snoring on BP and peripheral conduit artery distensibility, 30 children with primary snoring were studied at an age of 9.5 +/- 2.8 years (mean +/- SD). Systemic BP was measured using an automated device, while brachioradial arterial distensibility was assessed by measuring pulse wave velocity (PWV), which is inversely related to the square root of distensibility. The results were compared to those of 30 healthy control subjects matched for age, sex, and body size.

RESULTS

As compared to control subjects, children with primary snoring had significantly higher systolic BP (112 +/- 10 mm Hg vs 105 +/- 8 mm Hg, p = 0.001), diastolic BP (60 +/- 7 mm Hg vs 53 +/- 9 mm Hg, p = 0.004), and mean BP (81 +/- 7 mm Hg vs 71 +/- 8 mm Hg, p < 0.001). Likewise, those with primary snoring had significantly higher PWV (9.7 +/- 1.6 m/s vs 7.9 +/- 2.0 m/s, p = 0.001). Multiple regression identified age, body mass index (BMI), and primary snoring as significant determinants of systemic BP; however, primary snoring is the only significant determinant of PWV. Regardless of the BMI, systemic BP and PWV remained significantly higher in children with primary snoring.

CONCLUSION

Children with primary snoring have increased daytime systemic BP and reduced arterial distensibility, which may jeopardize long-term cardiovascular health.

Embryotrophic factor-3 from human oviductal cells affects the messenger RNA expression of mouse blastocyst

Our previous results showed that embryotrophic factor-3 (ETF-3) from human oviductal cells increased the size and hatching rate of mouse blastocysts in vitro. The present study investigated the production of ETF-3 by an immortalized human oviductal cell line (OE-E6/E7) and the effects of ETF-3 on the mRNA expression of mouse embryos. The ETF-3 was purified from primary oviductal cell conditioned media using sequential liquid chromatographic systems, and antiserum against ETF-3 was raised. The ETF-3-supplemented Chatot-Ziomek-Bavister medium was used to culture Day 1 MF1 x BALB/c mouse embryos for 4 days. The ETF-3 treatment significantly enhanced the mouse embryo blastulation and hatching rate. The antiserum, at concentrations of 0.03-3%, abolished the embryotrophic effect of ETF-3. Positive ETF-3 immunoreactivity was detected in the primary oviductal cells, OE-E6/E7, and blastocysts derived from ETF-3 treatment. Vero cells (African Green Monkey kidney cell line), fibroblasts, and embryos cultured in control medium did not possess ETF-3 immunoreactivity. The mRNA expression patterns of the treated embryos were studied at the blastocyst stage by mRNA differential display reverse transcription-polymerase chain reaction (DDRT-PCR). The DDRT-PCR showed that some of the mRNAs were differentially expressed after ETF-3 treatment. Twelve of the differentially expressed mRNAs that had high homology with cDNA sequences in the GenBank were selected for further characterization. The differential expression of seven of these mRNAs (ezrin, heat shock 70-kDa protein, cytochrome c oxidase subunit VIIa-L precursor, proteinase-activated receptor 2, eukaryotic translation initiation factor 2beta, cullin 1, and proliferating cell nuclear antigen) was confirmed by semiquantitative RT-PCR. In conclusion, immortalized oviductal cells produce ETF-3, which influences mRNA expression of mouse blastocyst.

Habitual snoring and sleep bruxism in a paediatric outpatient population in Hong Kong

OBJECTIVE

To determine the prevalence of habitual snoring and sleep bruxism in children attending the out-patient clinics of a paediatric department.

METHODOLOGY

A cross-sectional survey of parents was conducted with questionnaire administered by paediatric nurses. Parents were recruited when they brought their children to the out-patient clinics. Sex and age were recorded. Presence and absence of habitual snoring and sleep bruxism were noted. Types of diseases that brought the children to the out-patient clinics were also noted.

RESULTS

Twenty-nine of the 200 recruited children were noted to have habitual snoring (14.5%, 95% C.I. 10%-20%). The mean age of these habitual snorers was 6.2 +/- 3.1 years. For habitual snorers, male to female ratio was 1.4 to 1. Sixteen of these 28 children accepted a sleep polysomnographic examination. Eleven children were found to have snoring during the night of study. Two were found to have obstructive sleep apnoea syndrome. Sleep bruxism was found in 17 children (8.5%, 95% C.I.5%-13%). Sleep bruxism was closely related to habitual snoring as 16 out of the 17 children with sleep bruxism were also habitual snorers (p < 0.0001).

CONCLUSION

Habitual snoring and sleep bruxism were commonly found in children attending paediatric clinics. Paediatricians should be aware of these problems and be prepared to deal with them. Habitual snoring and sleep bruxism were closely related. Further studies into this relationship is needed.

Nocturnal enuresis and obstructive sleep apnoea in two children

Nocturnal enuresis was a symptom of childhood obstructive sleep apnoea, OSAS. We reported two children with secondary nocturnal enuresis which disappeared after tonsillectomy and adenoidectomy for proven OSAS. Pathogenesis of secondary nocturnal enuresis in OSAS was discussed.

Severe chronic neutropenia in Chinese children in Hong Kong

OBJECTIVE

Severe chronic neutropenia (SCN) is a rare and heterogeneous disorder in children. The epidemiology, clinical features and outcomes of SCN in Chinese children were reviewed.

METHODOLOGY

A retrospective analysis of case records was undertaken for 18 children with SCN managed during a 12-year period in a university teaching hospital in Hong Kong.

RESULTS

The median (range) age of the patients at initial presentation was 6.5 months (4 days-19 months). The initial and lowest median absolute neutrophil counts (ANC) were 0.29 x 109 /L and 0.06 x 109 /L, respectively. Patients with congenital SCN had significantly fewer neutrophils in peripheral blood at diagnosis. Only five subjects received granulocyte colony-stimulating factor (G-CSF) treatment. All children were free from serious infection on follow up for 51 months. Only one child suffered from long-term infection-related morbidity. One patient with chronic neutropenia was subsequently shown to have common variable immunodeficiency.

CONCLUSIONS

Most children with SCN in our series had favourable clinical outcomes. Our results support the recommendation that G-CSF should be used only in those with recurrent or severe infections.

Suppression subtractive hybridization identifies genes expressed in oviduct during mouse preimplantation period

Fertilization and development of mouse embryos occur in the ampullae of oviduct. Various growth factors and embryotrophic factors produced by the oviductal cells have been demonstrated to enhance embryo development in vitro. As a step towards understanding the genetic changes of mouse oviduct during mouse embryos preimplantation period, we adopted suppression subtractive hybridization (SSH) to establish four subtracted cDNA libraries to identify (1) oviduct-expressing genes, and (2) genes that may support embryo development in vivo. Using this method, we isolated 82, 88, 99, and 109 clones from four mouse libraries prepared from 0 (day 0), 24 (day 1), 48 (day 2), and 72 h (day 3) post-human chorionic gonadotropin (hCG) treated mice. Reverse dot-blot analysis confirmed that 25 (day 0), 24 (day 1), 40 (day 2), and 29 (day 3) clones were highly expressed in mouse oviduct when compared to other tissues. DNA sequence analysis identified genes encoding mouse oviduct-specific glycoprotein (MOGP), actin-binding protein 280, and several viral genes. Northern analysis confirmed that the genes were mainly expressed in oviduct, with some viral genes also expressed in uterus. About 9% of these oviduct expressing clones (11/118) were novel. We further demonstrated that one of the novel clones ODEG0-17 was expressed in the oviduct during early embryo preimplantation period and rarely in other tissues by RT-PCR. Our results show that SSH is a powerful method applicable to identifying tissue-specific transcripts on fertilization and development.

Unilateral right-sided internal jugular phlebectasia in asthmatic children

The most common cause of a neck mass that increases in size on straining is laryngocele. Internal jugular phlebectasia, which is of unknown cause, may present similarly. We present three cases of internal jugular phlebectasia, all of whom were asthmatic children. This association of asthma and internal jugular phlebectasia has not been reported previously.

A longitudinal study of cardiac function in children with cancer over 40 months

A previous study demonstrated impaired systolic function in 29% of patients treated with anthracycline as part of their therapy for malignant disease. A follow-up echocardiographic study was performed to determine whether there had been further deterioration of cardiac function. At least 40 months after the first study, those patients in whom abnormal systolic function had been detected and who had not received further anthracycline were studied by echocardiography using the same protocol as the initial study (group A). A second group of pediatric oncology patients who had not been given anthracycline but who had previously had cardiac assessment was selected as a control group (group N). The age and sex distributions of the two groups were comparable. Group A comprised 29 patients assessed on 2 occasions at mean times of 46 months and 89 months from the last dose of anthracycline. The mean dose of anthracycline received was 233 mg/m2 (range 20-400). Nine of 16 patients and 4 of 5 patients who had abnormal ejection fraction (EF) and fractional shortening (FS) at first assessment had normal EF and FS at the second assessment. There were no significant changes in EF, FS, and left ventricular wall stress (LVWS) between the two examinations. In group N, 20 patients were assessed after a mean interval of 43 months. There were no significant changes in EF, FS, or LVWS between the two examinations. At the first but not the second examination there were significant differences in the left ventricular internal diameters, EF, FS, and LVWS between group A and group N. Mildly abnormal cardiac indices detected in children after cessation of treatment with anthracycline did not deteriorate in 3 to 4 years follow-up. A longer cardiac follow-up study is indicated to assess the late outcome.

Coronary disease progression and its effect on left ventricular function

To determine the effect of coronary disease progression on left ventricular function, 47 patients who had two cardiac catheterizations at a mean interval of 25 months (range three to 92 months) without intervening surgery were studied. Of these, 35 patients had coronary disease and 12 patients had normal or near normal coronary arteries. Coronary disease progression was seen more often in patients with initial coronary disease than in those without significant disease (66 percent vs 25 percent, p less than 0.02). Left ventricular ejection fraction decreased in patients with coronary disease progression (0.63 +/- 0.03 to 0.51 +/- 0.04, p less than 0.01) but was unchanged in patients without progressive disease (0.58 +/- 0.04 to 0.57 +/- 0.93, p = NS). Interval myocardial infarction was the major cause of deteriorating left ventricular function. The rate or degree of coronary disease progression did not predictably change global left ventricular function, and progressive disease in individual vessels did not predictably alter regional left ventricular function. The presence or development of collateral vessels did not significantly alter ventricular performance.

Hypothesis testing in neurosurgical trials

Controlled clinical trials represent the most scientific methods of evaluating a new form of treatment. In designing such a trial, one must avoid committing two kinds of errors. The Type I error is defined as falsely concluding that a difference between two treatments exists, when they are equal. The Type II error is committed when one concludes that two treatments are the same, when a real difference exists. To reduce the probability of committing these errors, large sample sizes are required. A survey of neurosurgical trials showed that the majority of these trials have an unacceptably high probability of committing a Type II error because of inadequate sample size.